Convert cal/(s·cm·°C) to BTU·in/(h·ft²·°F)

Formula

BTU·in/(h·ft²·°F) = cal/(s·cm·°C) × 2900.964600499

Derivation from SI units:

• 1 cal_th/(s·cm·°C) = 4.184 J ÷ (1 s × 0.01 m × 1 K) = 418.4 W/(m·K) (exact)
• 1 BTU_IT·in/(h·ft²·°F) = 1055.05585262 J × 0.0254 m ÷ (3600 s × 0.09290304 m² × 5/9 K) = 0.1442278889 W/(m·K) (exact)
• 1 cal/(s·cm·°C) = 418.4 W/(m·K) ÷ 0.1442278888643 W/(m·K) per BTU·in/(h·ft²·°F) = 2900.964600499 BTU·in/(h·ft²·°F)

Both units are defined exactly, so the factor is exact. cal/(s·cm·°C) definition: calorie per second centimetre degree Celsius; BTU·in/(h·ft²·°F) definition: BTU inch per hour square foot degree Fahrenheit.

Worked examples

1. A reading of 0.005 cal/(s·cm·°C) converts to 14.504823 BTU·in/(h·ft²·°F).
   0.005 cal/(s·cm·°C) × 2900.9646 = 14.504823 BTU·in/(h·ft²·°F)
2. A value of 0.1 cal/(s·cm·°C) is 290.09646 BTU·in/(h·ft²·°F).
   0.1 cal/(s·cm·°C) × 2900.9646 = 290.09646 BTU·in/(h·ft²·°F)

Where it's used

cal/(s·cm·°C) are used for older scientific literature, while BTU inch per hour square foot degree Fahrenheit appear in US insulation k-values (ASTM C177, C518). Both measure thermal conductivity (k, λ), so the conversion is a fixed factor.

cal/(s·cm·°C) to other thermal conductivity units

Frequently asked questions

Sources

• Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "calorie_th per centimeter second degree Celsius [cal_th/(cm · s · °C)]".
• Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "British thermal unit_IT inch per hour square foot degree Fahrenheit [Btu_IT · in/(h · ft² · °F)]".

Last reviewed: 2026-10-15. Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.